Shogaols at proapoptotic concentrations induce G(2)/M arrest and aberrant mitotic cell death associated with tubulin aggregation

6-Shogaol improves sorafenib efficacy in colorectal cancer cells by modulating its cellular accumulation and metabolism

Carcinoma of the colon and rectum, also known as colorectal cancer, ranks as the third most frequently diagnosed malignancy globally. Sorafenib exhibits broad-spectrum antitumor activity against Raf, VEGF, and PDGF pathways in hepatocellular, thyroid, and renal cancers, but faces resistance in colorectal malignancies. 6-Shogaol, a prominent natural compound found in Zingiberaceae, exhibits antioxidant, anti-inflammatory, anticancer, and antiemetic properties. We investigated the influence of 6-shogaol on sorafenib's cytotoxic profile against colorectal cancer cell lines (HT-29, HCT-116, CaCo-2, and LS174T) through its effects on cellular accumulation and metabolism. Cytotoxicity was assessed using the sulpharodamine B assay, caspase-3 and c-PARP cleavage, cell cycle distribution analysis, and P-gp efflux activity. 6-Shogoal showed considerable cytotoxicity with decreased IC50 in colorectal cancer cell lines. Combining sorafenib and 6-shogaol increased c-PARP and pro-caspase-3 concentrations in HCT-116 cells compared to sorafenib alone. In combination, pro-caspase-3 concentrations were decreased in CaCo-2 cells compared to alone. Sorafenib combinations with 6-shogaol showed a significant drop in cell cycle distribution from 16.96±1.10 % to 9.16±1.85 %, respectively. At 100 µM, sorafenib and 6-shogaol showed potent and significant activity with intra-cellular rhodamine concentration on P-gp efflux activity in CRC cell lines. In conclusion, 6-shogaol substantially improved the cytotoxic profile of sorafenib by affecting its cellular uptake and metabolism. Future research should focus on dosage optimization and formulation and evaluate the efficacy and safety of the combination in animal models with colorectal cancer.

6-Shogaol prevents benzo (A) pyrene-exposed lung carcinogenesis via modulating PRDX1-associated oxidative stress, inflammation, and proliferation in mouse models

In this study, we have investigated the chemopreventive role of 6-shogaol (6-SGL) on benzopyrene (BaP) exposed lung carcinogenesis by modulating PRDX1-associated oxidative stress, inflammation, and proliferation in Swiss albino mouse models. Mice were exposed to BaP (50 mg/kg b.wt) orally twice a week for four consecutive weeks and maintained for 16 weeks, respectively. 6-SGL (30 mg/kg b.wt) were orally administered to mouse 1 h before BaP exposure for 16 weeks. After the experiment's termination, 6-SGL (30 mg/kg b.wt) prevented the loss in body weight, increased lung weight, and the total number of tumors in the mice. Moreover, we observed that 6-SGL treatment reverted the activity of BaP-induced lipid peroxidation and antioxidants in mice. Also, 6-SGL impeded the phosphorylation of MAPK family proteins such as Erk1, p38, and Jnk1 in BaP-exposed mice. PRDX1 is an essential antioxidant protein that scavenges toxic radicals and enhances several antioxidant proteins. Overexpression of PRDX1 substantially inhibits MAPKs, proliferation, and inflammation signaling axis. Hence, PRDX1 is thought to be a novel targeting protein for preventing BaP-induced lung cancer. In this study, we have obtained the 6-SGL treatment in a mouse model that reverted BaP-induced depletion of PRDX1 expression. Moreover, pretreatment of 6-SGL (30 mg/kg b.wt) significantly inhibited enhanced proinflammatory cytokines (TNF-α, IL-6, IL-β1, IL-10) and proliferative markers (Cyclin-D1, Cyclin-D2, and PCNA) in BaP-exposed mice. The histopathological studies also confirmed that 6-SGL effectively protected the cells with less damage. Thus, the study demonstrated that 6-SGL could be a potential phytochemical and act as a chemopreventive agent in BaP-induced lung cancer by enhancing PRDX1 expression.

Anticancer perspective of 6-shogaol: anticancer properties, mechanism of action, synergism and delivery system

Cancer is a malignant disease that has plagued human beings all the time, but the treatment effect of commonly used anticancer drugs in clinical practice is not ideal by reason of their drug tolerance and Strong adverse reactions to patients. Therefore, it is imperative to find effective and low-toxic anticancer drugs. Many research works have shown that natural products in Chinese herbal medicine have great anticancer potential, such as 6-shogaol, a monomer composition obtained from Chinese herbal ginger, which has been confirmed by numerous in vitro or vivo studies to be an excellent anti-cancer active substance. In addition, most notably, 6-shogaol has different selectivity for normal and cancer cells during treatment, which makes it valuable for further research and clinical development. Therefore, this review focus on the anti-cancer attributes, the mechanism and the regulation of related signaling pathways of 6-shogaol. In addition, its synergy with commonly used anticancer drugs, potential drug delivery systems and prospects for future research are discussed. This is the first review to comprehensively summarize the anti-cancer mechanism of 6-shogaol, hoping to provide a theoretical basis and guiding significance for future anti-cancer research and clinical development of 6-shogaol.

6-Shogaol Inhibits the Cell Migration of Colon Cancer by Suppressing the EMT Process Through the IKKβ/NF-κB/Snail Pathway

6-Shogaol from ginger has anti-inflammatory, anti-oxidation and anti-cancer effects. Aim of the Study: To study the effects and possible mechanisms of 6-Shogaol on inhibiting the migration of colon cancer cells Caco2 and HCT116 and prove the effects on proliferation and apoptosis. Materials and methods: The cells were treated with 6-Shogaol at the concentrations of 20, 40, 60, 80, and 100 µM, the cytotoxicity was tested by Colony formation assays and 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), and the Western blot was used to evaluate IKKβ/NF-κB/Snail pathway and EMT-related proteins. In addition, in order to eliminate the interference of proliferation inhibition on the experiment, Caco2 cells were treated with 6-Shogaol at the concentrations of 0, 40, and 80 µM, HCT116 cells were treated with 6-Shogaol at the concentrations of 0, 20, and 40 µM, apoptosis was measured by Annex V/PI staining, and migration was measured by Wound healing assays and Transwell test. Results: 6-Shogaol significantly inhibited the growth of cells. The maximum inhibitory concentration of half of them was 86.63 µM in Caco2 cells and 45.25 µM in HCT116 cells. At 80 µM and 40 µM concentrations, 6-Shogaol significantly promoted apoptosis of colon cancer Caco2 cells and HCT116 cells, and also significantly inhibited cell migration (P < .05). In addition, Western blot analysis showed that at 80 µM dose of 6-Shogaol significantly reduced MMP-2, N-cadherin, IKKβ, P-NF-κB and Snail expression in Caco2 cells (P < .05). 40 µM dose of 6-Shogaol significantly reduced VEGF, IKKβ, and P-NF-κB expression, and MMP-2, N-cadherin and Snail was significantly decreased at 60 µM of 6-Shogaol in HCT116 cells(P < .05). However, there was no significant change in E-cadherin in Caco2 cells, and the expression of E-cadherin protein in HCT116 cells decreased. Conclusion: This study proposes and confirms that 6-Shogaol can significantly inhibit the migration of colon cancer cells Caco2 and HCT116, and its mechanism may be produced by inhibiting EMT through IKKβ/NF-κB/Snail signaling pathway. It was also confirmed that 6-Shogaol inhibited the proliferation and promoted apoptosis of Caco2 and HCT116 cells.

The efficacy of applying some plants and herbs in cancer therapy for humans and animals – a comperhensive review

Cancer is a challenging ailment and represents the main reason for death worldwide for humans and animals. Although great developments have hindered cancer progression, several adverse effects are associated with modern chemotherapy. Natural remedies, such as the usage of medicinal plant or their products in cancer treatment, may decrease prejudicial side properties. Recently, the modern research scheme and innovative screening practices for herbs or plants have enabled phytochemical discovery for the prevention and treatment of cancer. This criticism highlights herbs such as acacia, basil, black seeds, cedar, castus, ficus, garlic, ginger, indigo, onion, pomegranate, quince, and thyme, promising anticancer effects. The present review also revealed the mode of action of each herb as anticancer effects at level in vitro and in vivo studies. The item also totalizes the vital mechanisms and signaling molecules involved in preventing cancer diseases. This will fill the investigate gap in the exploration of using natural molecules and encourage researchers in clinical trials of anticancer agents from herbs for humans and animals.

6-Shogaol from ginger shows anti-tumor effect in cervical carcinoma via PI3K/Akt/mTOR pathway

PURPOSE

6-Shogaol, an active phenolic compound from ginger (Zingiber officinale), can inhibit the growth of a variety of human cancer cells. Nevertheless, its underlying molecular mechanisms in cervical cancer remain unclear. In this study, we systematically examine the inhibitory effect of 6-shogaol on cervical cancer in vitro and in vivo.

METHODS

Cell proliferation was assessed by CCK8 assay and colony formation assay in HeLa and SiHa cells. We analyzed cell cycle and apoptosis through flow cytometry. GFP-LC3 puncta and transmission electron microscopy were used to observe autophagic bodies. Wound-healing assay and transwell assay were used for evaluating the migration of cells. Western blot was applied to detect protein expression levels.

RESULTS

6-Shogaol could suppress cell proliferation and migration, cause cell cycle arrest in the G2/M phase in HeLa and SiHa cells. Moreover, 6-shogaol triggered the apoptosis process through the mitochondrial pathway by downregulating the expression levels of p-PI3K, p-Akt and p-mTOR. Further research indicated that the induction of apoptosis by 6-shogaol was remarkably decreased after the treatment of ROS scavenger and PI3K agonist. Additionally, 6-shogaol increased the number of LC3-positive puncta and autophagic bodies per cell in both HeLa and SiHa cells. Pretreatment of cells with Bafilomycin A1, an autophagy inhibitor, accelerated 6-shogaol mediated cell apoptosis, suggesting that induction of autophagy by 6-shogaol is suppressive to apoptosis. Furthermore, in vivo data revealed that 6-shogaol significantly inhibited tumor growth and cell proliferation in tumor tissues.

CONCLUSION

These findings suggested that 6-shogaol could be developed as a functional food ingredient, which is potentially used as therapeutic agents for patients with cervical cancer.

Molecular and biological functions of gingerol as a natural effective therapeutic drug for cervical cancer

Cervical cancer is one of the most common and important gynecological cancers, which has a global concern with an increasing number of patients and mortality rates. Today, most women in the world who suffer from cervical cancer are developing advanced stages of the disease. Smoking and even exposure to secondhand smoke, infections caused by the human papillomavirus, immune system dysfunction and high-risk individual-social behaviors are among the most important predisposing factors for this type of cancer. In addition, papilloma virus infection plays a more prominent role in cervical cancer. Surgery, chemotherapy or radical hysterectomy, and radiotherapy are effective treatments for this condition, the side effects of these methods endanger a person's quality of life and cause other problems in other parts of the body. Studies show that herbal medicines, including taxol, camptothecin and combretastatins, have been shown to be effective in treating cervical cancer. Ginger (Zingiber officinale, Zingiberaceae) is one of the plants with valuable compounds such as gingerols, paradols and shogoals, which is a rich source of antioxidants, anti-cancer and anti-inflammatory agents. Numerous studies have reported the therapeutic effects of this plant through various pathways in cervical cancer. In this article, we look at the signaling mechanisms and pathways in which ginger is used to treat cervical cancer.

Cytotoxic effect of 6-Shogaol in Imatinib sensitive and resistant K562 cells

Chronic Myeloid Leukemia (CML) is a clonal hematopoietic malignancy characterized by the formation of BCR-ABL fusion protein. Imatinib (IMA) is a BCR-ABL tyrosine kinase inhibitor (TKI), which exhibited a high rate of response for newly diagnosed CML patients. Emergence of IMA resistance considered as a major challenge in CML therapy. Recent studies reported the anti-cancer effect of natural extracts such as 6-Shogaol (6-SG) which is extracted from ginger and the mechanisms involved in targeting of cancer cells. In the present study, we aimed to explore the potential anticancer effect of 6-SG on K562S (Imatinib sensitive) and K562R (Imatinib resistant) cells. K562S and K562R cells were incubated with increasing concentrations of 6-SG (5 μM- 50 μM) to determine its cytotoxic and apoptotic effects. Cell viability and apoptosis were investigated with spectrophotometric MTT assay and flow cytometric Annexin V staining, respectively. The mRNA expression levels of apoptotic related genes (BAX and BCL-2) and drug transporter (MDR-1 and MRP-1) genes were evaluated with qRT-PCR. According to our results, 6-SG treatment inhibited cell viability, induced apoptosis in both K562S and K562R cells. Based on our RT-PCR results, 6-SG enhanced pro-apoptotic BAX gene and decreased anti-apoptotic BCL-2 gene expression levels significantly in both treated K562S and K562R cells. Furthermore, 6-SG increased MDR-1 mRNA expression level in K562S and K562R cells in comparison with their control counterparts. Whereas, 6-SG decrease MRP-1 mRNA expression level in K562S cells significantly. It is the first study that reveals the apoptotic effect of 6-SG in CML cell line and IMA resistance. Therefore, 6-SG treatment can be suggested as a promising strategy for CML therapy.

Pristine Cu-MOF Induces Mitotic Catastrophe and Alterations of Gene Expression and Cytoskeleton in Ovarian Cancer Cells

Metals-organic frameworks (MOFs) have been widely explored in biomedicine, mostly in drug delivery, biosensing, and bioimaging due to their large surface area, tunable porosity, readily chemical functionalization, and good biocompatibility. However, the underlining cellular mechanisms controlling the process for MOF cytotoxicity remains almost completely unknown. Here, we demonstrate that pristine Cu-MOF without any loaded drug selectively inhibited ovarian cancer mainly through promoting tubulin polymerization and destroying the cell actin cytoskeleton (F-actin) to trigger the mitotic catastrophe, accompanying by conventional programmed cell death. To our knowledge, this is the first report claiming that mitotic catastrophe may be an explaining mechanism of MOF cytotoxicity. Cu-MOF with an intrinsic protease-like activity also hydrolyzed cellular cytoskeleton proteins (F-actin). The RNA sequencing data indicated the differential expressional mRNA of cell proliferation and actin cytoskeleton (ACTA2, ACTN3, FSCN2, and SCIN) and mitotic spindles (PLK1 and TPX2) related genes. We found that Cu-MOF as a promising candidate in the disruption of cellular cytoskeleton and the change of the gene expression could be actin altering and antimitotic agents against cancer cells, allowing for fundamental biological and biophysical studies of MOFs.

Small molecule inhibitors and stimulators of inducible nitric oxide synthase in cancer cells from natural origin (phytochemicals, marine compounds, antibiotics)

Nitric oxide synthases (NOS) are a family of isoforms, which generate nitric oxide (NO). NO is one of the smallest molecules in nature and acts mainly as a potent vasodilator. It participates in various biological processes ranging from physiological to pathological conditions. Inducible NOS (iNOS, NOS2) is a calcium-independent and inducible isoform. Despite high iNOS expression in many tumors, the role of iNOS is still unclear and complex with both enhancing and prohibiting actions in tumorigenesis. Nature presents a broad variety of natural stimulators and inhibitors, which may either promote or inhibit iNOS response. In the present review, we give an overview of iNOS-modulating agents with a special focus on both natural and synthetic molecules and their effects in related biological processes. The role of iNOS in physiological and pathological conditions is also discussed.

Ginger extract activates caspase independent paraptosis in cancer cells via ER stress, mitochondrial dysfunction, AIF translocation and DNA damage

The rhizome of ginger (Zingiber officinale) a common culinary agent is also known for its medicinal activity. We have earlier reported that pure 6-shogaol, an important component of ginger induces paraptosis in triple negative breast cancer (MDA-MB-231) and non small cell lung (A549) cancer cells. However, the chemopreventive potential of the whole ginger extract in food remains to be elucidated. Here, we demonstrate for the first time that ginger extract (GE) triggers similar anticancer activity/paraptosis against the same cell lines but through different molecular mechanisms. Q-TOF LC-MS analysis of the extract showed the presence of several other metabolites along with 6-shogaol and 6-gingerol. GE induces cytoplasmic vacuolation through ER stress and dilation of the ER. Drastic decrease in the mitochondrial membrane potential and ATP production along with the excess generation of ROS contributed to mitochondrial dysfunction. Consequently, GE caused the translocation of apoptosis inducing factor to the nucleus leading to the fragmentation of DNA. Taken together, these show a novel mechanism for ginger extract induced cancer cell death that can be of potential interest for cancer preventive strategies.

Gingers and Their Purified Components as Cancer Chemopreventative Agents

Chemoprevention by ingested substituents is the process through which nutraceuticals and/or their bioactive components antagonize carcinogenesis. Carcinogenesis is the course of action whereby a normal cell is transformed into a neoplastic cell. This latter action involves several steps, starting with initiation and followed by promotion and progression. Driving these stages is continued oxidative stress and inflammation, which in turn, causes a myriad of aberrant gene expressions and mutations within the transforming cell population and abnormal gene expressions by the cells within the surrounding lesion. Chemoprevention of cancer with bioreactive foods or their extracted/purified components occurs primarily via normalizing these inappropriate gene activities. Various foods/agents have been shown to affect different gene expressions. In this review, we discuss how the chemoprevention activities of gingers antagonize cancer development.

Ginger: A Novel Strategy to Battle Cancer through Modulating Cell Signalling Pathways: A Review

Numerous studies have been performed in understanding the development of cancer. Though, the mechanism of action of genes in the development of cancer remains to be explained. The current mode of treatment of cancer shows adverse effects on normal cells and also alter the cell signalling pathways. However, ginger and its active compound have fascinated research based on animal model and laboratories during the past decade due to its potentiality in killing cancer cells. Ginger is a mixture of various compounds including gingerol, paradol, zingiberene and shogaol and such compounds are the main players in diseases management. Most of the health-promoting effects of ginger and its active compound can be attributed due to its antioxidant and anti-tumour activity. Besides, the active compound of ginger has proven its role in cancer management through its modulatory effect on tumour suppressor genes, cell cycle, apoptosis, transcription factors, angiogenesis and growth factor. In this review, the role of ginger and its active compound in the inhibition of cancer growth through modulating cell signalling pathways will be reviewed and discussed.

Applying an Electrophilicity-Based Strategy to Develop a Novel Nrf2 Activator Inspired from Dietary [6]-Shogaol

Activation of nuclear factor erythroid-2-related factor 2 (Nrf2) is a crucial cellular defense mechanisms against oxidative stress and also an effective means to decrease the risk of oxidative stress-related diseases including cancer. Thus, identifying novel Nrf2 activators is highly anticipated. Inspired from [6]-shogaol (6S), an active component of ginger, herein we developed a novel potent Nrf2 activator, (1E,4E)-1-(4-hydroxy-3-methoxyphenyl)-7-methylocta-1,4,6-trien-3-one (SA) by an electrophilicity-based strategy. Compared with the parent 6S, SA bearing a short but entirely conjugated unsaturated ketone chain manifested the improved electrophilicity and cytoprotection (cell viability for the 10 μM 6S- and SA-treated group being 48.9 ± 5.3% and 76.1 ± 3.2%, respectively) against tert-butylhydroperoxide ( t-BHP)-induced cell death (cell viability for the t-BHP-stimulated group being 42.4 ± 0.4%) of HepG2. Mechanistic study uncovers that SA works as a potent Nrf2 activator by inducing Keap1 modification, inhibiting Nrf2 ubiquitylation and phosphorylating ERK in a Michael acceptor-dependent fashion. Taking 6S as an example, this works illustrates the feasibility and importance of applying an electrophilicity-based strategy to develop Nrf2 activators with dietary molecules as an inspiration due to their low toxicity and extraordinarily diverse chemical scaffolds.

The Novel Small Molecule STK899704 Promotes Senescence of the Human A549 NSCLC Cells by Inducing DNA Damage Responses and Cell Cycle Arrest

The novel synthetic compound designated STK899704 (PubChem CID: 5455708) suppresses the proliferation of a broad range of cancer cell types. However, the details of its effect on lung cancer cells are unclear. We investigated the precise anticancer effect of STK899704 on senescence and growth arrest of A549 human non-small cell lung cancer (NSCLC) cells. STK899704 affected NSCLC cell cycle progression and decreased cell viability in a dose-dependent manner. Immunofluorescence staining revealed that STK899704 destabilized microtubules. Cell cycle analysis showed an increase in the population of NSCLC cells in the sub-G₁ and G₂/M phases, indicating that STK899704 might cause DNA damage via tubulin aggregation. Furthermore, we observed increased mitotic catastrophe in STK899704-treated cells. As STK899704 led to elevated levels of the p53 pathway-associated proteins, it would likely affect the core DNA damage response pathway. Moreover, STK899704 promoted senescence of NSCLC cells by inducing the p53-associated DNA damage response pathways. These findings suggest that the novel anti-proliferative small molecule STK899704 promotes cell death by inducing DNA damage response pathways and senescence after cell cycle arrest, being a potential drug for treating human lung cancers.

Occurrence, biological activity and metabolism of 6-shogaol

As one of the main bioactive compounds of dried ginger, 6-shogaol has been widely used to alleviate many ailments. It is also a major pungent flavor component, and its precursor prior to dehydration is 6-gingerol, which is reported to be responsible for the pungent flavor and biological activity of fresh ginger. Structurally, gingerols including 6-gingerol have a β-hydroxyl ketone moiety and is liable to dehydrate to generate an α,β-unsaturated ketone under heat and/or acidic conditions. The conjugation of the α,β-unsaturated ketone skeleton in the chemical structure of 6-shogaol explicates its higher potency and efficacy than 6-gingerol in terms of antioxidant, anti-inflammatory, anticancer, antiemetic and other bioactivities. Research on the health benefits of 6-shogaol has been conducted and results have been reported recently; however, scientific data are scattered due to a lack of systematic collection. In addition, action mechanisms of the preventive and/or therapeutic actions of 6-shogaol remain obscurely non-collective. Herein, we review the preparations, biological activity and mechanisms, and metabolism of 6-shogaol as well as the properties of 6-shogaol metabolites.

Pharmacokinetic-pharmacodynamic correlations in the development of ginger extract as an anticancer agent

Anticancer efficacy of ginger phenolics (GPs) has been demonstrated in various in vitro assays and xenograft mouse models. However, only sub-therapeutic plasma concentrations of GPs were detected in human and mouse pharmacokinetic (PK) studies. Intriguingly, a significant portion of GPs occurred as phase II metabolites (mainly glucuronide conjugates) in plasma. To evaluate the disposition of GPs and understand the real players responsible for efficacy, we performed a PK and tissue distribution study in mice. Plasma exposure of GPs was similar on day 1 and 7, suggesting no induction or inhibition of clearance pathways. Both free and conjugated GPs accumulated in all tissues including tumors. While non-cytotoxicity of 6-ginerol glucuronide precluded the role of conjugated GPs in cell death, the free forms were cytotoxic against prostate cancer cells. The efficacy of ginger was best explained by the reconversion of conjugated GPs to free forms by β-glucuronidase, which is over-expressed in the tumor tissue. This previously unrecognized two-step process suggests an instantaneous conversion of ingested free GPs into conjugated forms, followed by their subsequent absorption into systemic circulation and reconversion into free forms. This proposed model uncovers the mechanistic underpinnings of ginger's anticancer activity despite sub-therapeutic levels of free GPs in the plasma.

Glucuronidation of [6]-shogaol, [8]-shogaol and [10]-shogaol by human tissues and expressed UGT enzymes: identification of UGT2B7 as the major contributor

Shogaols, mainly [6]-shogaol (6S), [8]-shogaol (8S) and [10]-shogaol (10S), the predominant and characteristic pungent phytochemicals in ginger, are responsible for most of its beneficial effects. However, poor oral bioavailability owing to extensive glucuronidation limits their application. The present study aimed to characterize the glucuronidation pathways of 6S, 8S and 10S by using pooled human liver microsomes (HLM), human intestine microsomes (HIM) and recombinant human UDP-glucosyltransferases (UGTs). The rates of glucuronidation were determined by incubating shogaols with uridine diphosphate glucuronic acid-supplemented microsomes. Kinetic parameters were derived by appropriate model fitting. Reaction phenotyping assays, activity correlation analyses and relative activity factors were performed to identify the main UGT isoforms. As a result, one mono-4′-O-glucuronide was detected after incubating each shogaol with HLM and HIM. Enzymes kinetic analysis demonstrated that glucuronidation of shogaols consistently displayed the substrate inhibition profile, and the liver showed higher metabolic activity for shogaols (CL_int = 1.37–2.87 mL min⁻¹ mg⁻¹) than the intestine (CL_int = 0.67–0.85 mL min⁻¹ mg⁻¹). Besides, reaction phenotyping assays revealed that UGT2B7 displayed the highest catalytic ability (CL_int = 0.47–1.17 mL min⁻¹ mg⁻¹) among all tested UGTs. In addition, glucuronidation of shogaols was strongly correlated with AZT glucuronidation (r = 0.886, 0.803 and 0.871 for glucuronidation of 6S, 8S and 10S, respectively; p < 0.01) in a bank of individual HLMs (n = 9). Furthermore, UGT2B7 contributed to 40.8%, 34.2% and 36.0% for the glucuronidation of 6S, 8S and 10S in HLM, respectively. Taken altogether, shogaols were efficiently metabolized through the glucuronidation pathway, and UGT2B7 was the main contributor to their glucuronidation.

The glucuronidation pathways of shogaols ([6]-shogaol, [8]-shogaol and [10]-shogaol) were characterized in human tissues and recombinant human UDP-glucosyltransferases, and UGT2B7 was identified as the main contributor to their glucuronidation.

6-shogaol induces autophagic cell death then triggered apoptosis in colorectal adenocarcinoma HT-29 cells

6-shogaol is a phytochemical of dietary ginger, we found that 6-shogaol could induced both autophagic and apoptotic death in human colon adenocarcinoma (HT-29) cells. Results of this study showed that 6-shogal induced cell cycle arrest, autophagy, and apoptosis in HT-29 cells in a time sequence. After 6h, 6-shogal induced apparent G2/M arrest, then the HT-29 cells formed numerous autophagosomes in each phase of the cell cycle. After 18h, increases in acidic vesicles and LAMP-1 (Lysosome-associated membrane proteins 1) showed that 6-shogaol had caused autophagic cell death. After 24h, cell shrinkage and Caspase-3/7 activities rising, suggesting that apoptotic cell death had increased. And after 48h, the result of TUNEL assay indicated the highest occurrence of apoptosis upon 6-shogaol treatment. It appeared that apoptosis is triggered by autophagy in 6-shogaol treated HT-29 cells, the damage of autophagic cell death initiated apoptosis program.

Absorption, Metabolic Stability, and Pharmacokinetics of Ginger Phytochemicals

We have previously demonstrated promising anticancer efficacy of orally-fed whole ginger extract (GE) in preclinical prostate models emphasizing the importance of preservation of the natural "milieu". Essentially, GE primarily includes active ginger phenolics viz., 6-gingerol (6G), 8-gingerol (8G), 10-gingerol (10G), and 6-shogaol (6S). However, the druglikeness properties of active GE phenolics like solubility, stability, and metabolic characteristics are poorly understood. Herein, we determined the physicochemical and biochemical properties of GE phenolics by conducting in vitro assays and mouse pharmacokinetic studies with and without co-administration of ketoconazole (KTZ). GE phenolics showed low to moderate solubility in various pH buffers but were stable in simulated gastric and intestinal fluids, indicating their suitability for oral administration. All GE phenolics were metabolically unstable and showed high intrinsic clearance in mouse, rat, dog, and human liver microsomes. Upon oral administration of 250 mg/kg GE, sub-therapeutic concentrations of GE phenolics were observed. Treatment of plasma samples with β-glucuronidase (βgd) increased the exposure of all GE phenolics by 10 to 700-fold. Co-administration of KTZ with GE increased the exposure of free GE phenolics by 3 to 60-fold. Interestingly, when the same samples were treated with βgd, the exposure of GE phenolics increased by 11 to 60-fold, suggesting inhibition of phase I metabolism by KTZ but little effect on glucuronide conjugation. Correlating the in vitro and in vivo results, it is reasonable to conclude that phase II metabolism seems to be the predominant clearance pathway for GE phenolics. We present evidence that the first-pass metabolism, particularly glucuronide conjugation of GE phenolics, underlies low systemic exposure.

EF24 inhibits tumor growth and metastasis via suppressing NF-kappaB dependent pathways in human cholangiocarcinoma

A synthetic monoketone analog of curcumin, termed 3, 5-bis (2-flurobenzylidene) piperidin-4-one (EF24), has been reported to inhibit the growth of a variety of cancer cells both in vitro and in vivo. However, whether EF24 has anticancer effects on cholangiocarcinoma (CCA) cells and the mechanisms remain to be investigated. The aim of our study was to evaluate the molecular mechanisms underlying the anticancer effects of EF24 on CCA tumor growth and metastasis. Cell proliferation, apoptosis, migration, invasion, tumorigenesis and metastasis were examined. EF24 exhibited time- and dose-dependent inhibitory effects on HuCCT-1, TFK-1 and HuH28 human CCA cell lines. EF24 inhibited CCA cell proliferation, migration, and induced G2/M phase arrest. EF24 induced cell apoptosis along with negative regulation of NF-κB- X-linked inhibitor of apoptosis protein (XIAP) signaling pathway. XIAP inhibition by lentivirus mediated RNA interference enhanced EF24-induced apoptosis, while XIAP overexpression reduced it in CCA cells. In vivo, EF24 significantly suppressed the growth of CCA tumor xenografts and tumor metastasis while displaying low toxicity levels. Our findings indicate that EF24 is a potent antitumor agent that inhibits tumor growth and metastasis by inhibiting NF-κB dependent signaling pathways. EF24 may represent a novel approach for CCA treatment.

[6]-Shogaol, a dietary phenolic compound, induces oxidative stress mediated mitochondrial dependant apoptosis through activation of proapoptotic factors in Hep-2 cells

Ginger (Zingiber officinale) is a well-known herb used in ethnomedicine. [6]-shogaol, a phenolic nature is a major constituent of ginger. In this study, we investigated the anticancer activity of [6]-shogaol in Laryngeal cancer (Hep-2) cells. We demonstrated the effects of [6]-shogaol on the cell growth and apoptosis in Hep-2 cells were analyzed by the generation of reactive oxygen species (ROS), the level of mitochondrial membrane potential (ΔYm), DNA damage and apoptotic morphological changes were analyzed by AO/EtBr, AO and Hoechst staining. Further, apoptotic protein expressions were analyzed by western blot analysis. Our results indicated that [6]-shogaol induces apoptosis as evidenced by loss of cell viability, enhanced ROS, lipid peroxidation results in altered mitochondrial membrane potential, increased DNA damage in Hep-2 cells. Further, the prooxidant role of [6]-shogaol inhibit Bcl-2 expression with the simultaneous up-regulation of Bax, Cytochrome c, Caspase-9 and -3 protein expressions were observed in Hep-2 cells. Thus, [6]-shogaol induces apoptosis in Hep-2 cells through inducing oxidative damage and modulate apoptotic marker expressions. Therefore, [6]-shogaol might be used as a therapeutic agent for the treatment of laryngeal cancer.

6-Shogaol Inhibits Breast Cancer Cells and Stem Cell-Like Spheroids by Modulation of Notch Signaling Pathway and Induction of Autophagic Cell Death

Cancer stem cells (CSCs) pose a serious obstacle to cancer therapy as they can be responsible for poor prognosis and tumour relapse. In this study, we have investigated inhibitory activity of the ginger-derived compound 6-shogaol against breast cancer cells both in monolayer and in cancer-stem cell-like spheroid culture. The spheroids were generated from adherent breast cancer cells. 6-shogaol was effective in killing both breast cancer monolayer cells and spheroids at doses that were not toxic to noncancerous cells. The percentages of CD44⁺CD24^-/^low cells and the secondary sphere content were reduced drastically upon treatment with 6-shogaol confirming its action on CSCs. Treatment with 6-shogaol caused cytoplasmic vacuole formation and cleavage of microtubule associated protein Light Chain3 (LC3) in both monolayer and spheroid culture indicating that it induced autophagy. Kinetic analysis of the LC3 expression and a combination treatment with chloroquine revealed that the autophagic flux instigated cell death in 6-shogaol treated breast cancer cells in contrast to the autophagy inhibitor chloroquine. Furthermore, 6-shogaol-induced cell death got suppressed in the presence of chloroquine and a very low level of apoptosis was exhibited even after prolonged treatment of the compound, suggesting that autophagy is the major mode of cell death induced by 6-shogaol in breast cancer cells. 6-shogaol reduced the expression levels of Cleaved Notch1 and its target proteins Hes1 and Cyclin D1 in spheroids, and the reduction was further pronounced in the presence of a γ-secretase inhibitor. Secondary sphere formation in the presence of the inhibitor was also further reduced by 6-shogaol. Together, these results indicate that the inhibitory action of 6-shogaol on spheroid growth and sustainability is conferred through γ-secretase mediated down-regulation of Notch signaling. The efficacy of 6-shogaol in monolayer and cancer stem cell-like spheroids raise hope for its therapeutic benefit in breast cancer treatment.

Gingerols and shogaols: Important nutraceutical principles from ginger

Gingerols are the major pungent compounds present in the rhizomes of ginger (Zingiber officinale Roscoe) and are renowned for their contribution to human health and nutrition. Medicinal properties of ginger, including the alleviation of nausea, arthritis and pain, have been associated with the gingerols. Gingerol analogues are thermally labile and easily undergo dehydration reactions to form the corresponding shogaols, which impart the characteristic pungent taste to dried ginger. Both gingerols and shogaols exhibit a host of biological activities, ranging from anticancer, anti-oxidant, antimicrobial, anti-inflammatory and anti-allergic to various central nervous system activities. Shogaols are important biomarkers used for the quality control of many ginger-containing products, due to their diverse biological activities. In this review, a large body of available knowledge on the biosynthesis, chemical synthesis and pharmacological activities, as well as on the structure-activity relationships of various gingerols and shogaols, have been collated, coherently summarised and discussed. The manuscript highlights convincing evidence indicating that these phenolic compounds could serve as important lead molecules for the development of therapeutic agents to treat various life-threatening human diseases, particularly cancer. Inclusion of ginger or ginger extracts in nutraceutical formulations could provide valuable protection against diabetes, cardiac and hepatic disorders.

Activation of Nrf2 target enzymes conferring protection against oxidative stress in PC12 cells by ginger principal constituent 6-shogaol

Natural compounds containing phenoxyl groups and/or Michael acceptor units appear to possess antioxidant and cytoprotective properties. The ginger principal constituent 6-shogaol (6-S) represents one of such compounds. In this study, we reported that 6-S efficiently scavenges various free radicals in vitro, and displays remarkable cytoprotection against oxidative stress-induced cell damage in the neuron-like rat pheochromocytoma cell line, PC12 cells. Pretreatment of PC12 cells with 6-S significantly upregulates a series of phase II antioxidant molecules, such as glutathione, heme oxygenase 1, NAD(P)H: quinone oxidoreductase 1, thioredoxin reductase 1, and thioredoxin 1. A mechanistic study revealed that 6-S enhanced the translocation of Nrf2 from the cytosol to the nucleus and knockdown of Nrf2 abolished such protection, indicating that this cytoprotection is mediated by the activation of the transcription factor Nrf2. Another ginger constituent 6-gingerol (6-G), having a similar structure of 6-S but lacking the alpha,beta-unsaturated ketone structure (Michael acceptor moiety), failed to shelter PC12 cells from oxidative stress. Our results demonstrate that 6-S is a novel small molecule activator of Nrf2 in PC12 cells, and suggest that 6-S might be a potential candidate for the prevention of oxidative stress-mediated neurodegenerative disorders.

Influence of side chain structure changes on antioxidant potency of the [6]-gingerol related compounds

[6]-Gingerol and [6]-shogaol are the major pungent components in ginger with a variety of biological activities including antioxidant activity. To explore their structure determinants for antioxidant activity, we synthesized eight compounds differentiated by their side chains which are characteristic of the C1-C2 double bond, the C4-C5 double bond or the 5-OH, and the six- or twelve-carbon unbranched alkyl chain. Our results show that their antioxidant activity depends significantly on the side chain structure, the reaction mediums and substrates. Noticeably, existence of the 5-OH decreases their formal hydrogen-transfer and electron-donating abilities, but increases their DNA damage- and lipid peroxidation-protecting abilities. Additionally, despite significantly reducing their DNA strand breakage-inhibiting activity, extension of the chain length from six to twelve carbons enhances their anti-haemolysis activity.

Cysteine-conjugated metabolites of ginger components, shogaols, induce apoptosis through oxidative stress-mediated p53 pathway in human colon cancer cells

Shogaols, the major constituents of thermally processed ginger, have been proven to be highly effective anticancer agents. Our group has identified cysteine-conjugated shogaols (M2, M2', and M2″) as the major metabolites of [6]-, [8]-, and [10]-shogaol in human and found that M2 is a carrier of its parent molecule [6]-shogaol in cancer cells and in mice, while being less toxic to normal colon fibroblast cells. The objectives of this study are to determine whether M2' and M2″ behave in a similar manner to M2, in both metabolism and efficacy as anticancer agents, and to further explore the biological pro-apoptotic mechanisms of the cysteine-conjugated shogaols against human colon cancer cells HCT-116 and HT-29. Our results show that [8]- and [10]-shogaol have similar metabolic profiles to [6]-shogaol and exhibit similar toxicity toward human colon cancer cells. M2' and M2″ both show low toxicity against normal colon cells but retain potency against colon cancer cells, suggesting that they have similar activity to M2. We further demonstrate that the cysteine-conjugated shogaols can cause cancer cell death through the activation of the mitochondrial apoptotic pathway. Our results show that oxidative stress activates a p53 pathway that ultimately leads to p53 up-regulated modulator of apoptosis (PUMA) induction and down-regulation of B-cell lymphoma 2 (Bcl-2), followed by cytochrome c release, perturbation of inhibitory interactions of X-linked inhibitor of apoptosis protein (XIAP) with caspases, and finally caspase 9 and 3 activation and cleavage. A brief screen of the markers attenuated by the proapoptotic activity of M2 revealed similar results for [8]- and [10]-shogaol and their respective cysteine-conjugated metabolites M2' and M2″. This study highlights the cysteine-conjugated metabolites of shogaols as novel dietary colon cancer preventive agents.

Induction of lung cancer cell apoptosis through a p53 pathway by [6]-shogaol and its cysteine-conjugated metabolite M2

Dietary chemoprevention of cancer offers the possibility to suppress or inhibit cancer growth before it develops into more advanced and lethal stages. To this end, identification of novel compounds and their mechanisms of action is constantly needed. In this study, we describe that a major component of dry ginger (Zingiber officinalis), [6]-shogaol (6S), can be quickly metabolized in A549 human lung cancer cell line. One of the resulting metabolites, the cysteine-conjugated 6S (M2), exhibits toxicity to cancer cells similar to the parent compound 6S, but is relatively less toxic toward normal cells than 6S. We further demonstrate that both compounds can cause cancer cell death by activating the mitochondrial apoptotic pathway. Our results show that the cancer cell toxicity is initiated by early modulation of glutathione (GSH) intracellular content. The subsequently generated oxidative stress activates a p53 pathway that ultimately leads to the release of mitochondria-associated apoptotic molecules such as cytochrome C, and cleaved caspases 3 and 9. In a xenograft nude mouse model, a dose of 30 mg/kg of 6S or M2 was able to significantly decrease tumor burden, without any associated toxicity to the animals. This effect was correlated with an induction of apoptosis and reduction of cell proliferation in the tumor tissues. Taken together, our results show that 6S metabolism is an integral part of its anticancer activities in vitro and in vivo. This allows us to characterize M2 as a novel compound with superior in vivo chemopreventive properties that targets similar anticancer mechanisms as 6S.

Modulation of cyclins, p53 and mitogen-activated protein kinases signaling in breast cancer cell lines by 4-(3,4,5-trimethoxyphenoxy)benzoic acid

Despite the advances in cancer therapy and early detection, breast cancer remains a leading cause of cancer-related deaths among females worldwide. The aim of the current study was to investigate the antitumor activity of a novel compound, 4-(3,4,5-trimethoxyphenoxy)benzoic acid (TMPBA) and its mechanism of action, in breast cancer. Results indicated the relatively high sensitivity of human breast cancer cell-7 and MDA-468 cells towards TMPBA with IC₅₀ values of 5.9 and 7.9 μM, respectively compared to hepatocarcinoma cell line Huh-7, hepatocarcinoma cell line HepG2, and cervical cancer cell line Hela cells. Mechanistically, TMPBA induced apoptotic cell death in MCF-7 cells as indicated by 4′,6-diamidino-2-phenylindole (DAPI) nuclear staining, cell cycle analysis and the activation of caspase-3. Western blot analysis revealed the ability of TMPBA to target pathways mediated by mitogen-activated protein (MAP) kinases, 5′ adenosine monophosphate-activated protein kinase (AMPK), and p53, of which the concerted action underlined its antitumor efficacy. In addition, TMPBA induced alteration of cyclin proteins’ expression and consequently modulated the cell cycle. Taken together, the current study underscores evidence that TMPBA induces apoptosis in breast cancer cells via the modulation of cyclins and p53 expression as well as the modulation of AMPK and mitogen-activated protein kinases (MAPK) signaling. These findings support TMPBA’s clinical promise as a potential candidate for breast cancer therapy.

[6]-shogaol inhibits growth and induces apoptosis of non-small cell lung cancer cells by directly regulating Akt1/2

Non-small cell lung cancer (NSCLC) is the leading cause of cancer mortality worldwide. Despite progress in developing chemotherapeutics for the treatment of NSCLC, primary and secondary resistance limits therapeutic success. NSCLC cells exhibit multiple mutations in the epidermal growth factor receptor (EGFR), which cause aberrant activation of diverse cell signaling pathways. Therefore, suppression of the inappropriate amplification of EGFR downstream signaling cascades is considered to be a rational therapeutic and preventive strategy for the management of NSCLC. Our initial molecular target-oriented virtual screening revealed that the ginger components, including [6]-shogaol, [6]-paradol and [6]-gingerol, seem to be potential candidates for the prevention and treatment of NSCLC. Among the compounds, [6]-shogaol showed the greatest inhibitory effects on the NSCLC cell proliferation and anchorage-independent growth. [6]-Shogaol induced cell cycle arrest (G1 or G2/M) and apoptosis. Furthermore, [6]-shogaol inhibited Akt kinase activity, a downstream mediator of EGFR signaling, by binding with an allosteric site of Akt. In NCI-H1650 lung cancer cells, [6]-shogaol reduced the constitutive phosphorylation of signal transducer and activator of transcription-3 (STAT3) and decreased the expression of cyclin D1/3, which are target proteins in the Akt signaling pathway. The induction of apoptosis in NCI-H1650 cells by [6]-shogaol corresponded with the cleavage of caspase-3 and caspase-7. Moreover, intraperitoneal administration of [6]-shogaol inhibited the growth of NCI-H1650 cells as tumor xenografts in nude mice. [6]-Shogaol suppressed the expression of Ki-67, cyclin D1 and phosphorylated Akt and STAT3 and increased terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling-positivity in xenograft tumors. The current study clearly indicates that [6]-shogaol can be exploited for the prevention and/or treatment of NSCLC.

6-Shogaol induces apoptosis in human leukemia cells through a process involving caspase-mediated cleavage of eIF2α

Background

6-Shogaol is a promising antitumor agent isolated from dietary ginger (Zingiber officinale). However, little is known about the efficacy of 6-shogaol on leukemia cells. Here we investigated the underlying mechanism of 6-shogaol induced apoptosis in human leukemia cells in vitro and in vivo.

Methods

Three leukemia cell lines and primary leukemia cells were used to investigate the apoptosis effect of 6-shogaol. A shotgun approach based on label-free proteome with LC-CHIP Q-TOF MS/MS was employed to identify the cellular targets of 6-shogaol and the differentially expressed proteins were analyzed by bioinformatics protocols.

Results

The present study indicated that 6-shogaol selectively induced apoptosis in transformed and primary leukemia cells but not in normal cells. Eukaryotic translation initiation factor 2 alpha (eIF2α), a key regulator in apoptosis signaling pathway, was significantly affected in both Jurkat and U937 proteome profiles. The docking results suggested that 6-shogaol might bind well to eIF2α at Ser51 of the N-terminal domain. Immunoblotting data indicated that 6-shogaol induced apoptosis through a process involving dephosphorylation of eIF2α and caspase activation–dependent cleavage of eIF2α. Furthermore, 6-shogaol markedly inhibited tumor growth and induced apoptosis in U937 xenograft mouse model.

Conclusion

The potent anti-leukemia activity of 6-shogaol found both in vitro and in vivo in our study make this compound a potential anti-tumor agent for hematologic malignancies.

Identification of Michael acceptor-centric pharmacophores with substituents that yield strong thioredoxin reductase inhibitory character correlated to antiproliferative activity

AIMS

The role of thioredoxin reductase (TrxR) in tumorigenesis has made it an attractive anticancer target. A systematic approach for development of novel compounds as TrxR inhibitors is currently lacking. Structurally diversified TrxR inhibitors share in common electrophilic propensities for the sulfhydryl groups, among which include the Michael reaction acceptors containing an α,β-unsaturated carbonyl moiety. We aimed to identify features among structurally diversified Michael acceptor-based compounds that would yield a strong TrxR inhibitory character.

RESULTS

Structurally dissimilar Michael acceptor-based natural compounds such as isobutylamides, zerumbone, and shogaols (SGs) were found to possess a poor TrxR inhibitory activity, indicating that a sole Michael acceptor moiety was insufficient to produce TrxR inhibition. The 1,7-diphenyl-hept-3-en-5-one pharmacophore in 3-phenyl-3-SG, a novel SG analog that possessed comparable TrxR inhibitory and antiproliferative potencies as 6-SG, was modified to yield 1,5-diphenyl-pent-1-en-3-one (DPPen) and 1,3-diphenyl-pro-1-en-3-one (DPPro, also known as chalcone) pharmacophores. These Michael acceptor-centric pharmacophores, when substituted with the hydroxyl and fluorine groups, gave rise to analogs displaying a TrxR inhibitory character positively correlated to their antiproliferative potencies. Lead analogs 2,2'-diOH-5,5'-diF-DPPen and 2-OH-5-F-DPPro yielded a half-maximal TrxR inhibitory concentration of 9.1 and 10.5 μM, respectively, after 1-h incubation with recombinant rat TrxR, with the C-terminal selenocysteine residue found to be targeted.

INNOVATION

Identification of Michael acceptor-centric pharmacophores among diversified compounds demonstrates that a systematic approach to discover and develop Michael acceptor-based TrxR inhibitors is feasible.

CONCLUSION

A strong TrxR inhibitory character correlated to the antiproliferative potency is attributed to structural features that include an α,β-unsaturated carbonyl moiety centered in a DPPen or DPPro pharmacophore bearing hydroxyl and fluorine substitutions.

6-Shogaol inhibits breast and colon cancer cell proliferation through activation of peroxisomal proliferator activated receptor γ (PPARγ)

6-Shogaol has been shown to possess many antitumor properties including inhibition of cancer cell growth, inhibition of cancer metastasis, induction of apoptosis in cancer cells and induction of cancer cell differentiation. Despite its prominent antitumor effects, the direct molecular target of 6-shogaol has remained elusive. To identify the direct targets of 6-shogaol, a comprehensive antitumor profile of 6-shogaol (NSC752389) was tested in the NCI-60 cell line in an in vitro screen. The results show that 6-shogaol is COMPARE negative suggesting that it functions via a mechanism of action distinct from existing classes of therapeutic agents. Further analysis using microarray gene profiling and Connectivity Map analysis showed that MCF-7 cells treated with 6-shogaol display gene expression signatures characteristic of peroxisome proliferator activated receptor γ (PPARγ) agonists, suggesting that 6-shogaol may activate the PPARγ signaling pathway for its antitumor effects. Indeed, treatment of MCF-7 and HT29 cells with 6-shogaol induced PPARγ transcriptional activity, suppressed NFκB activity, and induced apoptosis in breast and colon cancer cells in a PPARγ-dependent manner. Furthermore, 6-shogaol is capable of binding to PPARγ with a binding affinity comparable to 15-delta prostaglandin J2, a natural ligand for PPARγ. Together, our findings suggest that the antitumor effects of 6-shogaol are mediated through activation of PPARγ and imply that activation of PPARγ might be beneficial for breast and colon cancer treatment.

Wogonoside induces cell cycle arrest and differentiation by affecting expression and subcellular localization of PLSCR1 in AML cells

Wogonoside induces cell cycle arrest and differentiation. Wogonoside acts by changing PLSCR1 expression and subcellular localization in the nucleus and by PLSCR1-related molecular events.

Characterization of thiol-conjugated metabolites of ginger components shogaols in mouse and human urine and modulation of the glutathione levels in cancer cells by [6]-shogaol

SCOPE

Shogaols, a series of major constituents in dried ginger with the most abundant being [6]-, [8]-, and [10]-shogaols, show much higher anticancer potencies than gingerols. Previously, we reported the mercapturic acid pathway as a major metabolic route for [6]-shogaol in mice. However, it is still unclear how the side chain length affects the metabolism of shogaols and how shogaols are metabolized in humans.

METHODS AND RESULTS

We first investigate the metabolism of [10]-shogaol in mouse urine, and then investigate the biotransformation of shogaols in human urine. Our results show that eight major thiol-conjugated metabolites of [10]-shogaol were detected in mouse urine, while six major thiol-conjugated metabolites of [6]-shogaol, two thiol-conjugated metabolites of [8]-shogaol, and two thiol-conjugated metabolites of [10]-shogaol were detected in urine collected from human after drinking ginger tea, using LC/ESI-MS/MS. Our results clearly indicate the mercapturic acid pathway is a major metabolic route for [10]-shogaol in mice and for shogaols in human. Furthermore, we also investigated the regulation of glutathione (GSH) by [6]-shogaol in human colon cancer cells HCT-116. Our results show [6]-shogaol, after initially depleting glutathione levels, can subsequently restore and increase GSH levels over time.

CONCLUSION

Shogaols are metabolized extensively in mouse and human to form thiol-conjugated metabolites and GSH might play an important role in the cancer-preventive activity of ginger.

The Cytotoxicity Mechanism of 6-Shogaol-Treated HeLa Human Cervical Cancer Cells Revealed by Label-Free Shotgun Proteomics and Bioinformatics Analysis

Cervical cancer is one of the most common cancers among women in the world. 6-Shogaol is a natural compound isolated from the rhizome of ginger (Zingiber officinale). In this paper, we demonstrated that 6-shogaol induced apoptosis and G2/M phase arrest in human cervical cancer HeLa cells. Endoplasmic reticulum stress and mitochondrial pathway were involved in 6-shogaol-mediated apoptosis. Proteomic analysis based on label-free strategy by liquid chromatography chip quadrupole time-of-flight mass spectrometry was subsequently proposed to identify, in a non-target-biased manner, the molecular changes in cellular proteins in response to 6-shogaol treatment. A total of 287 proteins were differentially expressed in response to 24 h treatment with 15 μM 6-shogaol in HeLa cells. Significantly changed proteins were subjected to functional pathway analysis by multiple analyzing software. Ingenuity pathway analysis (IPA) suggested that 14-3-3 signaling is a predominant canonical pathway involved in networks which may be significantly associated with the process of apoptosis and G2/M cell cycle arrest induced by 6-shogaol. In conclusion, this work developed an unbiased protein analysis strategy by shotgun proteomics and bioinformatics analysis. Data observed provide a comprehensive analysis of the 6-shogaol-treated HeLa cell proteome and reveal protein alterations that are associated with its anticancer mechanism.

RET is a potential tumor suppressor gene in colorectal cancer

Cancer arises as the consequence of mutations and epigenetic alterations that activate oncogenes and inactivate tumor suppressor genes. Through a genome-wide screen for methylated genes in colon neoplasms, we identified aberrantly methylated RET in colorectal cancer. RET, a transmembrane receptor tyrosine kinase and a receptor for the glial cell-derived neurotrophic factor family ligands, was one of the first oncogenes to be identified, and has been shown to be an oncogene in thyroid cancer and pheochromocytoma. However, unexpectedly, we found RET is methylated in 27% of colon adenomas and in 63% of colorectal cancers, and now provide evidence that RET has tumor suppressor activity in colon cancer. The aberrant methylation of RET correlates with decreased RET expression, whereas the restoration of RET in colorectal cancer cell lines results in apoptosis. Furthermore, in support of a tumor suppressor function of RET, mutant RET has also been found in primary colorectal cancer. We now show that these mutations inactivate RET, which is consistent with RET being a tumor suppressor gene in the colon. These findings suggest that the aberrant methylation of RET and the mutational inactivation of RET promote colorectal cancer formation, and that RET can serve as a tumor suppressor gene in the colon. Moreover, the increased frequency of methylated RET in colon cancers compared with adenomas suggests RET inactivation is involved in the progression of colon adenomas to cancer.

10-Shogaol, an antioxidant from Zingiber officinale for skin cell proliferation and migration enhancer

In this work, one of Zingiber officinale components, 10-shogaol, was tested with 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, metal chelating ability, and reducing power to show antioxidant activity. 10-Shogaol promoted human normal epidermal keratinocytes and dermal fibroblasts cell growths. 10-Shogaol enhanced growth factor production in transforming growth factor-β (TGF-β), platelet derived growth factor-αβ (PDGF-αβ) and vascular endothelial growth factors (VEGF) of both cells. In the in vitro wound healing assay for 12 or 24 h, with 10-shogaol, the fibroblasts and keratinocytes migrated more rapidly than the vehicle control group. Thus, this study substantiates the target compound, 10-shogaol, as an antioxidant for human skin cell growth and a migration enhancer with potential to be a novel wound repair agent.